Multi-arm radial or star polymers are of great practical and theoretical interest. Since the late sixties, a large number and variety of such radial or star homopolymers and block polymers have been prepared, mainly by anionic techniques. Such prior art work has included the contributions of Dr. Paul Rempp et al. regarding pioneering work on star polystyrenes, e.g., J. G. Zilliox, P. Rempp, and J. Parrod, J. Polymer Sci., C(22), 145 (1968), and P. Lutz and P. Rempp, Makromol. Chem., 189, 1051 (1988). Polydiolefin and block copolymer stars were pioneered by Fetters et al., e.g., L.-K. Bi and L. J. Fetters, Macromolecules, 9(5), 732 (1976) and U.S. Pat. No. 3,985,830 (1976) and also discussed by Roovers et al., e.g., L. L. Zhou, N. Hadjichristidis, P. M. Toporowski, and J. Roovers, Rubber Chem. Tech., 65(2), 303 (1992). Poly(tert-butyl acrylate) stars were synthesized by C. Tsitsilianis, P. Lutz, S. Graff, J.-P. Lamps, and P. Rempp, Macromolecules, 24(22), 5897 ( 1991 ) while poly(ethylene oxides) were discussed by Y. Gnanou, P. Lutz, and P. Rempp, Makromol. Chem., 189, 2885 (1988). Polyisoprene stars were prepared by N. Hadjichristidis, A. Guyot, and L. J. Fetters, Macromolecules, 11(4), 668 (1978). And various hetero-arm stars are discussed by C. Tsitsilianis, S. Graff, and P. Rempp, Eur. Polym. J., 27(3), 243 (1991) and R. W. Pennisi and L. J. Fetters, Macromolecules, 21(4), 1094 (1988). However, all of this previous work involved anionic star polymer synthesis.
Only recently has the synthesis of cationic star polymers been successfully prepared by scientists at Kyoto University, e.g., (1) "Star-Shaped Polymers by Living Cationic Polymerization, 6. Amphiphilic Star-Shaped Block Copolymers of Vinyl Ethers with Carboxyl Groups: Synthesis and Host-Guest Interaction", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Makromol. Chem. 194, 2035-46 (1993), (2) "Star-Shaped Polymers by Living Cationic Polymerization, 5. Core-Functionalized Amphiphilic Star-Shaped Polymers of Vinyl Ethers with Hydroxyl Groups: Synthesis and Host-Guest Interaction", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Macromolecules 26, 254-59 (1993), (3) "Star-Shaped Polymers by Living Cationic Polymerization, 4. Selective Host-Guest Interaction of Small Molecules by Amphiphilic Star-Shaped Polymers of Vinyl Ethers", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Macromolecules 25, 6414-18 (1992), (4) "Star-Shaped Polymers by Living Cationic Polymerization, 3. Synthesis of Heteroarm Amphiphilic Star-Shaped Polymers of Vinyl Ethers with Hydroxyl or Carboxyl Pendant Groups", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Macromolecules 25, 6407-13 (1992), (5) "Star-Shaped Polymers by Living Cationic Polymerization, 2. Synthesis of Amphiphilic Star-Shaped Block Polymers of Vinyl Ethers with Hydroxyl Groups", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Macromolecules 24(21), 5741-45 (1991), and (6) "Star-Shaped Polymers by Living Cationic Polymerization, 2. Synthesis of Star-Shaped Polymers of Alkyl Vinyl Ethers", Kanaoka, Sawamoto, and Higashimura, Kyoto University, Macromolecules 24, 2309-13 (1991). However, all of the Kyoto University work requires the use of vinyl ether linking compounds shown generically below. ##STR1##
Kennedy et al. has synthesized three-and four-arm star polyisobutylenes by direct initiation, see J. P. Kennedy, L. R. Ross, J. E. Lackey, and O. Nuyken, Polym. Bull., 4(1/2), 67 (1981) and K. J. Huang, M. Zsuga and J. P. Kennedy, Polym. Bull., 19(1), 43 (1988). However, multi-armed stars using non-polar linking agents, and additionally using polyolefin, e.g., polyisobutylene, as the composition of the arms, has not heretofore been possible.